1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2022 Loongson Technology Corporation Limited 4 */ 5 #include <linux/kernel.h> 6 7 #include <asm/unwind.h> 8 9 unsigned long unwind_get_return_address(struct unwind_state *state) 10 { 11 if (unwind_done(state)) 12 return 0; 13 else if (state->first) 14 return state->pc; 15 16 return *(unsigned long *)(state->sp); 17 } 18 EXPORT_SYMBOL_GPL(unwind_get_return_address); 19 20 void unwind_start(struct unwind_state *state, struct task_struct *task, 21 struct pt_regs *regs) 22 { 23 memset(state, 0, sizeof(*state)); 24 25 if (regs) { 26 state->sp = regs->regs[3]; 27 state->pc = regs->csr_era; 28 } 29 30 state->task = task; 31 state->first = true; 32 33 get_stack_info(state->sp, state->task, &state->stack_info); 34 35 if (!unwind_done(state) && !__kernel_text_address(state->pc)) 36 unwind_next_frame(state); 37 } 38 EXPORT_SYMBOL_GPL(unwind_start); 39 40 bool unwind_next_frame(struct unwind_state *state) 41 { 42 struct stack_info *info = &state->stack_info; 43 unsigned long addr; 44 45 if (unwind_done(state)) 46 return false; 47 48 if (state->first) 49 state->first = false; 50 51 do { 52 for (state->sp += sizeof(unsigned long); 53 state->sp < info->end; 54 state->sp += sizeof(unsigned long)) { 55 addr = *(unsigned long *)(state->sp); 56 57 if (__kernel_text_address(addr)) 58 return true; 59 } 60 61 state->sp = info->next_sp; 62 63 } while (!get_stack_info(state->sp, state->task, info)); 64 65 return false; 66 } 67 EXPORT_SYMBOL_GPL(unwind_next_frame); 68